Herpesviruses have been implicated as etiological agents of some animal and human cancers. This has raised the possibility of prevention of these cancers through the use of viral vaccines. Because of the potential danger of using attenuated or inactivated herpesviruses containing virus genetic information for the immunization of human populations, it would appear to be more realistic to consider using purified viral proteins for the induction of immunity in susceptible populations. This, however, requires the identification, purification and characterization of those antigens responsible for inducing a protective immune response against the tumor-associated virus. In some of the herpesvirus systems, including Herpes simplex virus and Epstein-Barr virus, these antigens appear to be expressed in the membranes of infected cells. The objectives of this research proposal are: (1) to isolate, purify and characterize the virus-induced membrane antigens (MA) produced in cells infected with EBV or Herpesvirus saimiri (HVS), an oncogenic non-human primate herpesvirus; (2) to produce monospecific antisera against these purified components for utilization in studies directed at defining the relation of MA to other viral-associated antigens induced by these 2 viruses; and (3) to assess the potential use of MA's as a vaccine for preventing tumor induction by EBV and HVS in cottontop marmosets. The main immunological assay that will be used for monitoring membrane fractions for intact MA will be the antibody-dependent lymphocyte cytotoxicity assay. Major techniques that will be employed in the membrane fractionation or solubilization experiments will be hypotonic and hypertonic extraction, mebrane density separation in high molecular weight dextran and the 2-phase polymer system of Brunette and Till. The isolated MA will be characterized by a variety of techniques including acrylamide gel electrophoresis and electrofocusing.